Meta+test262-runner: Check for signature of __assert_fail in CMake

Rather than trying to assume the only two C libraries on Linux are musl
and glibc, this solution fixes musl builds by explicitly checking for
the one C library function we are overwriting.

That being said, we should find another solution to retrieving this
error information from crashing tests. Possibly just overriding the
SIGABRT handler would work. The full solution might require checking
stderr as well as stdout in the test driver though.

Meta/Lagom/CMakeLists.txt

@@ -497,6 +497,22 @@ if (BUILD_LAGOM)
         add_executable(test262-runner ../../Tests/LibJS/test262-runner.cpp)
         target_link_libraries(test262-runner LibJS LibCore)
 
+        if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
+            include(CheckCSourceCompiles)
+            # Check for musl's declaration of __assert_fail
+            check_c_source_compiles(
+                "
+                #include <assert.h>
+                __attribute__((__noreturn__)) void __assert_fail(char const* assertion, char const* file, int line, char const* function) {}
+                int main() {}
+                "
+                ASSERT_FAIL_HAS_INT
+            )
+        endif()
+        if (ASSERT_FAIL_HAS_INT OR EMSCRIPTEN)
+            target_compile_definitions(test262-runner PRIVATE ASSERT_FAIL_HAS_INT)
+        endif()
+
         add_executable(wasm ../../Userland/Utilities/wasm.cpp)
         target_link_libraries(wasm LibCore LibWasm LibLine LibMain)